In this section:
Metabolise Energy Bioassay
Accurate prediction of metabolisable energy of ingredients is a vital factor in formulation of commercial poultry rations. Testing by chemical or physical methods is often unsatisfactory, thereby resulting in nutritionally inadequate rations, which can be expensive to make, and result in sub-optimal performance of flocks. Measurement of apparent metabolisable energy (AME) of feed ingredients and mixed feeds in a bioassay using commercial broiler chickens provides valuable information for feed formulation purposes.
What is an AME bioassay ?
An AME bioassay is a short-term digestive physiology study on chickens in metabolism cages. It involves quantitative measurements of feed intake and excreta output. It requires measurements of energy in feed and excreta by bomb calorimetry to determine energy balance.
What can it be used for ?
- Determine the AME of feed ingredients to improve the accuracy of feed formulation
- Determine the AME of mixed feeds for verification of least cost feed formulations
- Determine the efficacy of feed additives such as enzymes and probiotics
- Examine anti-nutritive factors such as non-starch polysaccharides in feeds
- Measure the digestibility of various nutrients such as essential amino acids
- Collection of digesta or tissue samples from chickens
- Any short-term study requiring measurements of feed intake and excreta output.
How is it done ?
The Poultry Nutrition Research Group from the Pig and Poultry Production Institute (PPPI) uses modern, purpose built, environmentally controlled facilities to conduct AME bioassays for clients.
- Commercial broiler chickens are reared to 22 days of age under typical commercial conditions
- Chickens can be reared in single sex or mixed sex flocks as required
- Commercial broiler feeds are used during rearing
- Birds are weighed at the start and end of each seven-day study
- Chickens are placed in single-bird or in group metabolism cages (4 - 6 birds per cage)
- Experimental feeds in pellet form (cold pressed) are fed for seven days
- Chickens adapt to the new feeds and cage environment for three days
- Feed intake is measured over the adaptation and collection periods
- Excreta are quantitatively collected from each cage daily for four days and oven-dried
- Excreta from each cage are pooled, finely ground and then sampled for analysis
- Samples of feed and excreta are sent to the PPPI Nutrition Research Laboratory for analysis.
Who currently uses the AME bioassay service?
- Commercial feed mills
- Multi-national companies supplying feed
- Suppliers of additives to the poultry industry
- Grain marketers
- Plant breeders
- Research and development corporations
- Other researchers who wish to do collaborative studies with PPPI staff.
Can the bioassay be customised for individual clients?
- Changes can be made to existing procedures to suit client’s specific needs
- Single-bird cages (total 96) and group cages (total 96) are available
- Studies can be done on an individual sample of feed or ingredient or on batches of samples submitted by clients
- Studies can involve up to 96 cages at a time.
Please note, importation of samples into Australia requires prior approval from the Australian Quarantine and Inspection Service.
For further information contact Bob Hughes at the Pig and Poultry Production Institute (PPPI).
